1. Field of the Invention
The present invention relates to a circuit breaking device provided in a car or the like.
2. Description of the Related Art
As for such a circuit breaking device, it is general to use a fuse or a fusible link which is fused to break a circuit when an overcurrent is generated in the circuit. On the other hand, in such an emergency where, for example, an accident is caused in a vehicle, there is a case where it is demanded to forcibly break a circuit immediately. Such a request is particularly earnest, for example, in power supply circuits and soon in electric vehicles which have come into wide use promptly in recent years.
As for such a conventional circuit breaker, JP-B-58-47809 discloses a circuit breaker for breaking a conductor inserted into a circuit by use of an explosion force of an explosive. According to this circuit breaker, as shown in FIG. 17, a fuse 202 connected between output terminals 201, an explosive 203, and a filament 204 for heating this explosive 203 are enclosed in a reinforced enclosure glass 205. When a current is supplied between input terminals 206, the filament 204 is heated to thereby explode the explosive 203. Thus, the fuse 202 is broken by use of the explosion force. It is therefore possible to break the circuit forcibly at desired timing.
However, since the fuse 202 is broken by the explosion force of the explosive itself, such a circuit breaker has been somewhat short in reliability in view of breaking of the fuse 202 surely, therefore, in view of expectation for sure circuit breaking.